Exploring the Effects of Hydraulic Connectivity Scenarios on the Spatial-Temporal Salinity Changes in Bosten Lake through a Model

Abstract

Lake water salinization in arid areas is a common problem and should be controlled for the better use of freshwater of lakes and for the protection of the environment around lakes. It is well known that the increasing of hydraulic connectivity improves water quality, but for a lake, understanding how hydraulic connectivity changes its water quality in terms of spatial aspects is of great significance for the protection and utilization of different regions of the lake water body. In this paper, the impacts of three connectivity scenarios on the spatial-temporal salinity changes in Bosten Lake were modeled through the three-dimensional (3D) hydrodynamic model, Environmental Fluid Dynamics Code (EFDC). The constructed Bosten Lake EFDC model was calibrated for water level, temperature, and salinity with acceptable results. As for the Bosten Lake, three connectivity scenarios were selected: (1) the increasing of the discharge water amount into the lake from the Kaidu River, (2) the transferring of 1 million cubic meter freshwater to the southwestern part of the lake (the Huangshuigou region of the lake), and (3) the changing of the outflow position from the southwestern part of the lake (the Kongque river) to the southeastern of the lake (the Caohu region). Through the simulations, we found that the region of the lake mainly influenced by the three scenarios presented here were different, and of the three scenarios, scenario 3 was the best means of controlling the overall lake salinity. On the basis of the salinity distribution results gained from the simulations, decision-makers can choose the ways to mitigate the salinity of the lake according to which region they want to improve the most in terms of economic efficiency and preserve in terms of ecological balance.It is a common problem that water is salinized with time in arid and semi-arid areas [5,6]. In Central Asia, many freshwater lakes have changed to oligosaline or saline lakes due to anthropogenic activities and climate change [7]. Lake Qarun, southwest of Cairo, Egypt, a formerly freshwater lake, has become a saline lake due to agricultural drainage [8]. The water salinity of the Aral Sea and Lake Chad has increased due to river regulation and diversions [9]. In arid and semi-arid regions, lake water salinization has been attributed primarily to high water evaporation rates, low rainfall rates, limited recharge and inflow water diversion for irrigation, among other uses [10][11][12].The impacts of water salinization are manifold, adverse, and have largely irreversible environmental, economic, and social costs [8]. Many studies [13][14][15][16][17] demonstrate that the high salinity in lake water has harmful effects on water quality and the health of people, plants, and animals, hence restricting the utilization of water and damaging the integrity of ecosystems.It is well known that water connectivity is important for controlling water quality and improving ecological environment. The river loop connection, existing prior to 1965, between the Keelung River a...

Distributions, Relationship and Assessment of Major Ions and Potentially Toxic Elements in Waters of Bosten Lake, the Former Largest Inland and Freshwater Lake of China

“…Bosten Lake is located at the south slope of the Tianshan Mountains. The elevation of Bosten Lake is about 1048 m [39]. The water area of the lake is approximately 1100 km 2 , the volume is 88 × 10 8 m 3 , and the maximum water depth is 14 m [40].…”

Salinity-Linked Denitrification Potential in Endorheic Lake Bosten (China) and Its Sensitivity to Climate Change

“…Amended denitrification rates were negatively correlated with salinity and sulfate concentrations in Lake Bosten ( Table 1 ), perhaps indicating that salinity is a key regulating factor of denitrification. Climate change is affecting the hydrological cycle of Lake Bosten and consequent effects on concentration or dilution will alter lake salinity (Rusuli et al, 2015 ; Liu and Bao, 2020 ). In addition, there is a continuous input of salinity from salt leaching associated with the agricultural irrigation of the northwestern basin (Tang et al, 2012 ; Guo et al, 2015b ).…”

Diagnostic Simulation of Water Age in Small Lake of Bosten Lake

“…The hydrodynamic model was constructed previously with the EFDC for the Bosten Lake (the big lake) and had been well-calibrated with the available observations for temperature, salinity, and water level [63]. Since the small lake is next to the big lake and it is small, it is assumed that the big lake EFDC model can be used for the small lake with its own input conditions.…”